Plug and receptacle



p 9, 1952 o. s. GREESQN 2,610,266

PLUG AND REEPTAcLE Filed Feb. 2, 1951 4 Sheets-Sheet 1 In uentar Orion 5. Greeson I22 mic]:

Sept. 9, 1952 o. s. GREESON 2, 10,

' PLUG AND RECEPTACLE Filed Feb. 2, 1951 4 Sheets-Sheet 2 Fig. 2

Inventor Orion 5i Greeson I04 B 5mm Se t. 9, 1952 o. s. GREESON ,6

PLUG AND RECEPTACLE Filed Feb. 2, 1951 4 Sheets-Sheet 3 MIMI plu Illi Fig. 8

I In ventor Orion 5- Greeson Sept. 9, 1952 o. s. GREESON' PLUG AND RECEPTACLE Filed Feb. 2, 1951 I n ventor Orion 5. Greeson Attorney:

Patented Sept. 9, 1952 UNITED STATES PATENT omce PLUG AND RECEPTACLE Orion S. 'Greeson, Elizabeth, N. J.

Application February 2, 1951, Serial No. 209,073

This invention relates to control means for closing electrical circuits andmore particularly to a plug and receptacle that is substantially ex plosion-proof. a

The switch incorporated in the plug'comprising one elementof the present invention is of the type disclosed in the copending applications, Serial No. 107,598, filed July 29, 1949, now Patent No. 2,587,143, February 26, 1952, and Serial No. Serial No. 144,079, filedFebruary 14, 1950, now Patent No. 2,587,144, February 26, 1952, of which this application is a continuation in part.

The primary object of this invention is to provide a substantially explosion-proof plug and receptacle which is designed so that the male terminals of the plug cannot either make or break contact with the terminals of the receptacle while the circuit to the connected appliance is closed.

As can be readily understood, if the contact between the male terminals and the terminals of the the receptacle were to be made while the circuitwas closed, a spark mightresult, which in an explosive laden atmosphere, would set off an explosion.

i A further object of this invention is to' provide a device in which the circuit is automatically opened when pull is exerted on an extensioncord to the appliance being used.

A. further object of this invention is to provide a a plug and receptacle which is sealed in such manner that when the plug is inserted the device is water-proof, dust-proof, vapor-proof and proof against corrosive fumes and even submerged conditions will not affect it in any way.

Another object of this invention is the provision of means for running an extension cord through one or more pulleys and controlling the power to an appliance by pulling on the cord s astoeliminate a switch on the appliance to be used and to insure the proper expiration of the plug incase of an accidental rupture of the cord. Still further objects of the invention reside, in the provision of a plug and receptacle embodying a switch 'unit with, interdependent switching mechanisms, which is strong, durable, highly efficient in operation, simple in construction and manufacture, and capable of being used forvarious and numerous purposes.

These, together with the various ancillary objects of the invention which will become apparent as the following description proceeds, are obtained by this invention, preferred embodiments of which have been illustrated in the accompany ing drawings, by way of example only, wherein: V

Claims. (01. 200-51.09)

Figure 1 is an elevational view of the device comprising thepresent invention shown in use in:

conjunction with apulley system; i

Figure 2 is a longitudinal sectional view of the a device shown in its initial position;

Figure 3 is a longitudinal sectional view of the device after the plug has been inserted in the re ceptacle; a

Figure 4 is a longitudinal sectional view of'the the switch in its initial position;

Figure 7 is an enlarged sectional detail ofthe plug as taken along the line 1-'I in Figure 2 5 Figure 8 is an enlarged sectional detail as taken along a plane at right angles to the plane of Fig- Figure 9 is an enlarged detail view showing the switch in its second phase of operation;

switch in another operative position; 1

Figure 10 is an elevational detail showingthe:

Figure 11 is a detail view showing the position? of the various elements of the invention in ye another position; I 1 Figure 12 is a perspective view oftheswitch' comprising an important element of the present,

invention; 1 1

Figure 13 is an elevationalview of a modified;

form of the invention showing the receptacle for use in conjunction with an extension cord.

With continuing reference to the accompanying. drawings wherein like reference numerals designate similar parts throughout the various views; reference numeral 10 is used to designate' a" resilient cylinder formed of rubber or the like having an extension cord 12 entering at one end-i and male terminals 14 set in the other end.

Inside the cylinder I0 is a rigidsleeve l6with a portion bonded to the cylinder at the terminal end. A disk or plate [8 is bonded to the cord end of the cylinder 10. The switch mechanism is fastened to the sleeve 16. An actuation arm- 20 is fastened to the plate I8 in such manner that when the cord I2 is pulled and the cylinder 10 elongated, the switch mechanism will be actuated.v The switch mechanism 2| includes a base 22 formed with a flange 23 attached by screws to the Y sleeve I6 and which is formed with an upturned leg 24 forming a'guide post. A driving head 26 is equipped with a rod 28 which slides in a hole in a motion-transmitting mechanism to be further.

defined? The secondary plate 36 is held to the base 22 by contact 39 and rivet 40 which slide in slots.

in thebase 22.

a cradle for the latch device 44.

A portion of the opposed sides of the plate 36 are upturned as at 38 to provide" The latch device 44 includes a 1m platefl'fi which is provided with ears 42 whichrare posis:

tioned on pintle 48 which is terminally secured to the ears 38 of the secondary plate 36; Means are provided for drawingizthe latch plate 46 inwardly and consistrof a' fiat' springzfioattached. to

the latch plate whichlis curved aroundi'th'e Epintle 48and which isattacheds at its freeendito'a pin. 521- Thepinilpassesithrough an openin'gin the latch plate 46 and is attache'diit'o'thetsecondary plate-36.1Theispring 50draws the :latch platea46 toward the. secondary plate 36 or inwardly. Q The latch plate 46 carries two elastic pawls 54 an'd'56 which -are"-preferably 'made of springsteel-rror of other -highly: elastic: material. and i which: are

rivetedj:welded;zor otherwiseisecured :to the. outer:

sidezof the jatc'hplate-i lfi. Each spring pawlcona of a; lezifesprizigwithtra; bent .end, the ends being Tbent at tanciangle; to thezrremainderiof the leafispring forming the working ends: of thepawl's;

Th'i-plateifi furthen carriesianiarm .58" which is fixedly attached to it LTheZarm 58 supports "at its ifireeendn'guidezpi-rr-fifls.

is substantially .U-shimed and. which is provided wit-Italyoketo which the rod ZBisrattached. 1 The driving head has two legs 62 and 64 whichare:

substantially parallel: .The'legi62is provided with appliedfcagainststhe stepla66- if the; latch plate 46 i in a givenr.position. The-leg 64of the driving.

heaidizlfi is I provided; with: a. slanting. end. surface yoke but at its end is provided witlr aiprojection or rhomboidalzcross sec-tion. The rhomboidal projectioni'm and: the :adjacent and. contiguous surfaces of the leg 64 cooperate with the 'guide pint-60 on the .arm;5B of thelatch plateAfi. V

The'sp'ring pawl 56 engages a;locking segment I2 whichis carried-shy;the.base..plate? 2 2. The:

locking segmentiis formed with at'rack I4 having a 'stepped -surface:.:.16 and. aslanting surface: .1 T forming: an rinclinez The latch plate may. .be

locked-1m: position when pawl 56 iszengagedbehind thej istepz 16 of the :tooth '14- of the locking s'eg-x merits-1.

An armzTB extends from-the secondary.p1ate 36 and.:'slides:; in. an .aopenin'grin the "guide post: 24.

The2a=rm-18 performs'r-a dua-lfunction; it 00-;

operateslwit-h the contact-.36 and the rivet 4lll in guidingthe secondary: plate? 36 and: also carries theablock: .80 i .:Insulatively--mounted :on .thebase 22 are-secondary:conta'ct springs: 82 and 84. Q-ne conductorof the extensioncordfl is operatively;

connected tojspring 82 andrthe otherconductor of the cord' l2is operatively connected to oneof the terminals-11.4.1- Conductor'.8'5 is provided to connectr-the-contactspring. 8.4 with the. otherterminal. l4: rTheseccontact springs. B2 and, are only;

semieelasticiand .so anaopeiativecircuit throughg 7 them is closed by bringing contact 39 in contact with them. This is accomplished by pushing the secondary plate 36 to which contact 39 is secured forward. The outer sleeve of contact 39 which is insulated from its supporting post is thus directed between the semi-circular ends of the contact springs 82 and 84, thereby establishing a good connection.

. The pushing of the secondary plate 36 forward also tensions .1a retractile spring '88 Zwhich is stretched between pin 90 which projects from the secondary plate 36 and the pin 92 which projects from the base 22. When the secondary plate is releasedgrit is pulled back by spring 88 and since contact 39 is attached to the secondary plate, it is also pulled back from contact with the spring contacts 82 and.84,-thus opening the circuit. The backward movement of the secondary plate is limited by "pin 90 striking the edge of the base 22. When the switch is in its initial position, the terminals: 14" are inserted in :therreceptacle: 95. The'zreceptacleincludes afipair of inner springs.94

and a; pair :of outer spring, 96. A lug: H0 is at-- tached to each outer spring. One outer spring 96 is connected :to one inner-spring'94 and. lead wires .98- are connected to the outer springs. .96.. The springswfi l' and- 96 are attached toan -:.in-

sulator 'lflfl'which, in turn; is attachedxtoa base: I02. A face plate HM'is attached to'the base l-l2.

The terminals 'l 4 are molded in the end wall of the cylinder'il 0 insuchea' manner that the .elasticity of the rubberf'or similar-.material that. con-.- stitutes theeendwall'tends 'to spread the outer endof the terminals-apart and. topressthe inner endof the terminals together. Therefore, when unrestrainedf-the terminals-will assume an.

angulated position as shown in Figure 5. ;When

the switchis in itsinitialposition, the block-:

is positioned between the inner end of theteriminals,-..thus limiting the spread-of the outer .end

of theterminals so thattthey assume a slightly angulat'ed position :as shown in FigureZ: In: this; positiom the lugs lllfi'a're positioned in the. recesses IO8 inthe block 60,: thus'preventing the opera-.-

the-switch so that it may be operated. 1 Then the plug is given'a slight pull by'pullingon'theextension cord which operates the switch andcloses the circuit. The closure of the switch may causeaspark at contacts Hand 34 butno explosion" will result because the'switch is hermetically sealed within the cylinder IB When it is desired to remove the plug from the receptacle, the plug'is' given a slight pull" which operates the" switch and opens the circuit. The resultant spark will cause no explosion because it is confined. within the cylinder [0. 'The opening of the 1 switch positions the block 80 between the inner end of the terminals 14, thus limiting the "spread of the outer end of the terminalsfiso that the plug may be withdrawn. If an attempt is made to withdraw'thei plug when the switch is closed; the terminalswill be" held in a normal positionby the outer'springs of "the receptacle until they pass the curved portion. of the outer. springs, .at .which time they will spread. With the switch 'closed,.the block'which. limits the .spread .of the terminalsi withdrawn. and so the lugs all 0 onethe outer. springswill. e'n-L This action :lifts: the lugs I106 gage the holes H2 in theterininals and prevent withdrawal. i

In case the switch is inadvertently closed when the plug is out of the receptacle, the terminals will spread as shown in Figure 5 and, since they will then be out of-line with the holes in insulating face plate I04, the plug cannot be inserted until the terminals are returned to a normal position and the switch re-operated to open the circuit. This positions the block be-' on the arm 58 rests on the inner face of the rhomboidal projection near the inner edge of the projection. The spring 50 is only slightly tensioned. Upon pullingon the extension cord, the actuation arm pushes the driving head 26 and causes the contact 39 to close the contact between spring contacts 82 and 84. latch plate 46 to move. During this movement, the pawl 56 is riding on the incline of locking member 12.- At the end of the forward stroke, the pawl 56 rides over the locking tooth and is caught behind the step of the locking tooth. The movement of the pawl 56 along the incline imparts to the latch plate 45 a tendency to move angularly and outwardly. This movement is, however, counteracted by the guide pin 60 riding on the inner face of the projection 10. Therefore, the pawl spring 56 is tensioned. The position of the parts at this stage of the operation will be as shown in Figure 9, When the'drive head is moved back, due to the action of the spring 34 as is shown in Figure 10, the guide pin 60 loses contact with the inner wall of the driving head and moves outwardly along the wall and finally passes the outermost edge. The tension and bent pawl filican now unbend and the latch plate 46 is now moved angularly and outwardly, tensioning somewhat the spring 50. The guide pin 69 is nowfin front of the inclined wall 68 of the projection Ill without touching it. 'Pawl 54 has been lifted into the air and is no longer touching the leg 62.

If a further impulse is imparted by pulling on the extension cord, this will merely open, the circuit in the switch. This is because the,ac tu ation arm 20 is once more actuated, which moves the driving head toward the latch plate, its pawls and the guiding pin. The latter now ride on the projection 10 and upon movement of the driving head toward it, it is moved outwardlyby the in-.

therefore returns to its initial position; I'Thia phase of the, operation is shown in Figure, 11

and returnsiithe elements to their initial posi-; tion. i

Thus, it may be observed that-the plugand receptacleconstitute an explosion-proof arrangement that is practially foolproof.-As is indicated in Figures 1, 3-and 13, the base I02 of thereceptacle is threaded. at its outer end, as'atl20,';

forreception of a threaded collar I22. This threaded collar seals the receptaclein an ab- This will cause the solutely effective manner. It is to be understood that the receptacle I02 may be attached to a wall or may be attached to an extensioncord.

Further, as is indicated in'Figure 1, it is quite possible to use this device in connection with a pulley system, as is indicated at I24, whichwlllinsure the proper operation of the switch in the plug injcase of accidental severe stress on the extension cord. Further, it is to beg-understood that the use of this pulley system is optional with the invention and other and various modi fications will be readily and easily understood from the foregoing description. Therefore, it not intended to limit the invention to the precise embodiment shown'and described, but all necessary modifications and numerous equivalents may the scope be'readily' resorted to whichlfall within of theappended claims.

Having described the claimed as. new is:

1."A plug comprising a resilient oasing,- a

sleeve in said casing, a disk secured to said casingadapted to engage said sleeve, an extension cord secured to said disk, a, switch secured to said sleeve, prongs secured to said casing and extending therefrom, conductors completing an opera-' tive'electrical circuit between'said prongs and said extension cord, and an actuation arm se cured to said disk for actuating said switch" engage-'- upon displacement of said disk from ment with said sleeve.

2. A plug comprising a. resilient casing", a

sleeve in said casing, a disk secured to said cassecured to said secondary plate, a stationary locking member secured to said base plate, two resilient pawls carried by said latch plate, one of said pawls being a locking pawl adapted to engage the stationarylocking member, the other pawl beinga-driving pawl engaged by the driving head, an arm fixedly connected to said latch plate adapted to engage said drivin head, a pair of spaced springcontacts carried by said base plate, a movable contact member carried by said secondary plate adapted to engage said spring of the secondary plate to its initial circuit-open position, a rod secured to said driving head ex-' tending through and beyond .said guide post, resilient means urging said rod and said drivinghead towards its initialposition, an actuation arm secured to said disk engaging said rodupon displacement of said disk from engagement with said sleeve, prongssecured to said casing and extending therefrom, and conductors completing an operative-electrical circuit between saidterminals and said extension cord.

i 3. A plug comprising a resilient casing, a sleeve in said casing, a disk secured to said-casing adapted to engage "said sleeve, anextension cord securedto saiddisk, a switch secured tosaid sleeve,- prongs secured to said casing. and extend! invention, what is ing therefrom, conductors completingatan; open ative, electrical circuit between saidprongs and;

saidextensioncord, an actuation arm secured to. said'disk for actuating saidswitch.upondisplacee merit-of said ,disk from engagement WithrTSaidsleeve, said prongs being moldedlin said at anoutwardly diverging angle. l 4. A plug, comprising;,a resilient. casing, a-

sleeve-in said casing, a disk securedzto said 665-" ing-adapted to engage said sleeve, an extension cor-d. secured-to said disk, av switch secured to said, sleeve, said switch including a base plate secnredto said sleeve and having aportion form-1 ingaguidepost, adriving head movably secured on said base plate, a secondary plate slidablysecuredtosaid base plate, a latch platepivotally. secured to said secondary plate, a stationary locking member secured to said base-plate, two. resilient 'pawls carried by said latch plate, one of said pawls being a lockingpawl adapted. to engage :the stationary lockin member, the other pawl being adriving pawl engaged by the driv-. ing head, an arm fixedly connected to said latch,

plateadaptedto engage said: driving head, .a pair.

of spaced spring contacts carried by said b'ase,

plate, a movable contactmember carried by said secondary plate adapted to engage said spring contacts to .close --a circuit therebetween upon movementof saidsecondary plate, said arm, en-v gagingoneportion of the drivingheadto hold the other pawl under tension and being adapted to engagesaiddriving, head to impart an angular mdveinent to the latch plate, thereby lifting the.

locking-pawl out of, engagementwith the station: ary-locking member so as to permit vthereturn f-.thesecondary plate to its initial circuit-open position ;a rodi'securedto said drivinghead extending through ,and beyond said guide post, resilien-t, -means urging said rod" and said driving headstowards its initial position, an actuationarmsecured to said disk, engaging said rodupon displacement? of said disk from engagementwith. said sleeve, prongs secured to said casing and ex tending therefromsaid prongs being moldedv in said casing at an outwardly diverging angle, and

conductors completing an operative electrical circuitbetween said terminals and saidextension.

cord.

5-.;A .plugjcomprising a resilient casing, a sleeve: in saidcasing, a disk secured to. said case ingi adapted to engage said sleeve, an extension cord secured to said disk,:a switch secured tosaid. sleeve; prongs secured to said casing and extends ingtherefrom,conductors completing an opera..

tiveelectrical circuit: between said terminals and saidziextension cordgan actuationarm secured. to 'said-[diskior actuating said switch upon displacement of 7 said disk from engagement with saidzsleeve, said'prongs being molded in said cas-s ing-rat anoutwardly diverging angle, and, insulative means. carried by said switch receivable beouteriends'of'said prongs together.

6. A plug comprisingaresilient casing, asleev inasaidvcasingz:a disk secured. to said casing adapted? to engage said sleeve, an extension cord secured'to said disk, a SWitchJsecured to said sleeve,' said iswitcli including a base plate setween the inner; ends of said prongs/to urge the cured to said sleeve and having a portion forminga guide post, a driving head'movably secured on said-' -base-plate-a secondary plate slidably secured-to saidb'aseplate, a latch plate pivotally secured to -said secondary plate, a stationary locking member secur'ed to said base plate, two resilient pawls 'carried -by said latch plate-,one of easing said pawls-beingalocking pawladapted to .en,-.; gage the stationary locking member, the-other.

pawl being a, driving pawl engaged by the driving head, an arm fixedly connectedto said latch.

plate adapted to engage saiddriving head, a pair of,spaced spring contacts carried by said base plate, a movable contact membercarried'bysaid secondary plate adapted to engage said spring, contacts to close a circuit therebetween upon movement of said secondary plate, said arm en-, gaging one, portion of the drivinghead to hold the other pawl undertension-and beingiadaptedtov engage said driving head to impart anangular movement to the latch plate, thereby liftingthe locking pawlout of engagement with, the,.s.ta:- tionary lcckingmember so as to permit the re-.

turn of the secondary plate to its .initial circuits.

open position, a rod secured to said driving head extending: through and beyond "said guide 1 post;

resilient means urging said rod and said driving head towards itsinitial position, an actuation: arm secured to said disk engaging said rod upon ing an-operative electrical circuit between said terminals and said extension cord;

7. A switch comprisinga' base plate having a portion forming a guide post, adrivingheadmov ably secured on said-base plate, a secondary plate slidably secured to said base-plate, a latch plate pivotally secured to said secondary plate, a stationary lockingmember secured to said base plate, two resilient pawls carried by said latch plate, one of said pawls being a locking pawl adapted to engage the P stationary locking memher, the other pawl being a driving-pawl engaged by' thedr'iving head, an arm fixedly connected to said latch plate adapted to engage said driving head, a pair' of spaced spring contacts carried by said "base plate, a movable contact member carried bysaid secondary plate adapted to engage said spring contacts to close a'circuit therebetween upon movement of said secondary plate, said arm engaging oneportion of the driving head to holdthe other pawl under tension and being adapted'to engage said driving head to impart an angular movement to the latch plate, thereby lifting the locking pawl out of engagement with the stationarylocking member so as to permit the return of the secondary plate to its'initial circuit open position, a rod secured to said driving head extending through and beyond said guidepost, and resilient means urging said rod and said driving head towards itsinitial position.

8. An explosive-proof plug and receptacle said plug'comp'rising a resilient casing, a sleeve in saidcasing, a disk secured to said casing adapted to engage said sleeve, an extension cordsecured to said disk,-prongs secured tosaid casing and extendingtherefrom, conductors completing an operative electrical circuit between said terminals and saideXtension cord, and an actuation-arm secured to said disk for actuating said switch upon displacement of said disk from engagement with said sleeve, said receptacle including a'hous-L ing, an insulative plate insaid housing, a pair of outer contactsprings secured to. saidinsulative plate, a pair-of inner contactsprings'. secured :to

said insulative plate, each of said inner contact springs being electrically connected to one of said outer contact springs, a face plate having apertures therethrough secured to said housing, said prongs being receivable through the apertures in the face plate between said inner contact springs and said outer contact springs.

9. An explosive-proof plug and receptacle, said plug comprising a resilient casing, a sleeve in said casing, a disk secured to said casing adapted to engage said sleeve, an extension cord secured to said disk, prongs secured to said casing and extending therefrom, conductors completing an operative electrical circuit between said terminals and said extension cord, and an actuation arm secured to said disk for actuating said switch upon displacement of said disk from engagement with said sleeve, said receptacle including a housing, an insulative plate in said housing, a pair of outer contact springs secured to said insulative plate, a pair of inner contact springs secured to said insulative plate, each of said inner contact springs being electrically connected to one of said outer contact springs, a face plate having apertures therethrough secured to said housing, said prongs being receivable through the apertures in the face plate between said inner contact springs and said outer contact springs, said prongs being molded in said casing at an outwardly diverging angle.

10. An explosive-proof plug and receptacle, said plug comprising a resilient casing, a sleeve in said casing, a disk secured to said casing adapted to engage said sleeve, an extension cord secured to said disk, prongs secured to said casing and extending therefrom, conductors completing an operative electrical circuit between said terminals and said extension cord, and an actuation arm secured to said disk for actuating said switch upon displacement of said disk from engagement with said sleeve, said receptacle including a housing, an insulative plate in said housing, a pair of outer contact springs secured to said insulative plate, a pair of inner contact springs secured to said insulative plate, each of said inner contact springs being electrically connected to one of said outer contact springs, a face plate having apertures therethrough secured to said housing, said prongs being receivable through the apertures in the face plate between said inner contact springs and said outer contact springs, said prongs being molded in said casing at an outwardly diverging angle, and insulative means carried by said switch receivable between the inner ends of said prongs to urge the outer ends of said prongs together.

ORION S. GREESON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 525,437 Albertsen Sept. 4, 1894 2,230,277 Volker et a1 Feb. 4, 1941 

